Primary anterior teeth that require extensive restorative therapy due to caries, trauma, or developmental defects can present a particularly challenging problem to the dentist. The ideal restorative technique would assure strength, durability, aesthetics, and efficiency in placement. Many of the currently available regimens fail to fulfill one or more of the goals mentioned above; couple these concerns with the technical difficulties of operating on children with behavior management problems, and the dentist is often left with few reliable restorative options.
Restorative modalities currently in use to treat primary anterior teeth include bonding with composite resin, as in strip crowns, polycarbonate crowns, conventional stainless steel crowns, open-faced stainless steel crowns, and commercially veneered stainless steel crowns. However, each of these techniques presents technical, functional, or aesthetic compromises that complicate their efficient and effective use.
Bonding with composite resin requires an environment free of salivary or blood contaminants. Even though the results in a cooperative patient can be aesthetically pleasing, heavy functional loads, coupled with inadequate retention, often result in unpredictable longevity. Polycarbonate crowns are associated with the common clinical problems of fracture, debonding, and dislodgement. Conventional stainless steel crowns have excellent longevity and ease of placement when compared to bonding; they often result, however, in poor aesthetics. Open-faced stainless steel crowns result in some metal being exposed, which is an aesthetic concern. In addition, facings may become dislodged and the patient time required for fabrication is significantly greater than that of conventional stainless steel crowns. Finally, commercially veneered stainless steel crowns are often difficult to fit, due to problems with trimming and crimping of the preveneered surfaces.
The most relevant patent prior art of which the applicant is aware is U.S. Pat. No. 5,332,390, entitled "Shell Tooth Form", issued to Rosellini on Jul. 26, 1994. This patent describes the method for providing a crown or a replacement tooth utilizing the in situ production of preparing the tooth by grinding and shaping; filling a transparent shell tooth form with light-setting resin; placing the shell form onto the prepared tooth; and bonding the resin between the form and the tooth. While this reference discloses the use of a transparent shell formed from a light-setting resin, it does not indicate application to stainless steel crowns, or that a partial covering surface formed of a light-setting resin, such as a veneer, may be employed.
There is therefore a need in the dental arts for an easy and convenient, chairside technique that provides dental restoration with the strength and adaptability of a plain stainless steel crown, while at the same time providing the aesthetics of a plastic crown.